Customary marriage practices are integral to the cultural identity and social cohesion of Assam's indigenous communities, such as the Bodos, Mishings, and Karbis. These practices symbolize spiritual continuity, communal solidarity, and heritage. However, the accelerated pace of modernization has introduced profound transformations, leading to generational divergences in their perception and practice. While elder generations emphasize the sanctity and elaborate nature of traditional rituals, younger generations often advocate for simplified, pragmatic approaches influenced by modern education, urbanization, and shifting economic realities. This study explores how these evolving perspectives reflect broader socio-cultural transitions. Elders, traditionally key decision-makers in matrimonial matters, view customary marriages as anchors of cultural identity, while the youth assert greater autonomy, often challenging hierarchical and gendered roles embedded in these practices. External factors such as globalization, legal reforms, urban migration, and exposure to diverse ideologies further complicate this generational divide, raising questions about cultural erosion versus adaptation. The research highlights emerging hybrid models of marriage practices that selectively integrate traditional rituals with modern values like gender equality and cost-efficiency. These adaptations underscore the resilience of customary marriages as dynamic institutions that evolve with societal changes. By examining intergenerational negotiations and the external influences shaping these practices, the study situates Assamese tribal marriages within broader discussions on identity, cultural preservation, and modernization. It calls for policy measures and community-driven initiatives to balance tradition and modern aspirations, ensuring these practices remain relevant and meaningful in contemporary society.